JS的繼承和接口

//Test接口
	var Person = E.createInterface('say', 'eat');
	var Chinese = function() {};
	Chinese.prototype.say = function() {
		alert('說漢語')
	}
	Chinese.prototype.eat = function() {
		alert('吃中餐')
	}
	E.implement(Chinese, Person);
	
	
	//Test繼承
	var Instrument = function(name, tone) {
		this.name = name;
		this.tone = tone
	}
	Instrument.prototype.play = function() {
		alert(this.name + '的音色：' + this.tone);
	};
	
	var Guitar = function(name, tone) {
		this.superclass.call(this, name, tone);
	}
	Guitar = E.extend(Guitar, Instrument);
	
	var fingerGuitar = new Guitar('杉田健司', '高音甜中音穩低音狠 ');
	fingerGuitar.play();
	alert(fingerGuitar instanceof Guitar);

實現繼承和接口的工具類

/**
 * 
 */
E = {};
E.extend = function(sub, sup) {
	//借用構造函數
	sub.prototype = new sup();
	//保留父類的構造函數,以便在子類構造函數中用調用，將父類變量綁定在this下
	sub.prototype.superclass = sup;
	//因爲重寫了構造函數所以重新指定constructor,以使instanceof表現正常
	sub.prototype.constructor = sub;
	//因爲已經將變量綁定到子類上，所以刪除原型上多餘的變量
	return sub;
};

//實現類是否實現了所有接口的方法
E.implement = function() {
	var sub = arguments[0];
	for (var i = 1; i < arguments.length; i++) {
		var sup = arguments[i];
		try {
			sup.implemented(sub);
		} catch (e) {
			throw new Error('no implements interface ' + sup);
		}
	}
};

E.factory = {};
//創建接口
E.createInterface = E.factory.createInterface = function(methods) {
	var f = typeof arguments[0] === 'string';
	var p = f ? arguments : arguments[0];
	var len = p.length;
	var Interface = function() {};
	var _proto = Interface.prototype = {};
	_proto.implemented = function(constructor) {
		for (var i = 0; i < len; i++) {
			var obj = new constructor();
			if(!obj[p[i]]) {
				throw new Error('no implements interface');
			}
		}
	};
	
	return new Interface();
};